Process of cleaning molasses for manufacturing compressed yeast



Patented Sept. 20, 1927.

No Drawing.

REINHOLD IKUSSEROW, F OAKLAND, CALIFORNIA.

l PBOOESS'OF CLEANING MOTQASSES FOR MANUFACTURING COMPRESSED YEAST.

This invention relates to processes of cleaning and sterillzing solutions used in manufacturing yeast of the compressed variety.

causes the 1 These colloids cannot age of sucrose,

' originally present in *thermore, the

In the past, compressed yeast has been largely manufactured by the propagation of yeast culture in grain mashes However, in my copending application, SenNo. 711,833, 'filed'Ma-y 8, 1924, I have described a process of manufacturing yeast from molasses by which process a high quality of yeast may be cheaply obtained. The process herein described is an improvement over the process described in the above application.

In manufacturing yeast from molasses or other substances containing a high percentespecially the crude sugar cane molasses, it is difficult to properly sterilize and clean the molasses solution in order to kill certain injurious germs and bacteria the crude molasses. Some of these germs, especially those of butyric acid bacteria, cannot be destroyed by the use of the usual mineral acids or by simply heating to high temperatures. Furtionable and especially in cane sugar molasses, 1t formation of certain colloids. be, readily separated from the solution and ayeast propagated in sucha liquid produces a slimy product which contains certain of the erms found in the original molasses. Sue a yeast product spoils very rapidly andcannot readily be compressed in filter resses.

To make it possi 1e to employ common commercial molasses and even t e crude sugar cane molasses in the. manufacture of yeast.

I have evolved a new process of cleaning and sterilizing a solution of molasses prior or pitching of the solut on yfthis process thesolution is I sufiiciently clarified and is *freed-from in-' jurious I discovery 1 addition 0 9 Yeast manugerms and bacteria.

pzactically factured from such av solution-is free from slim colloids, may r ead1ly compressed, an will not easily spoil.

is process was made possible thru the that dilute molasses solution after suflicient alkali to prevent-the rop'agation kinds of bacteria. The process developed utilizes the development of certain bacteria resent in the molasses solution, especially actic acid bacteria,lwhich' bacteria propause of mineral acids is objecin that in many kindsof molasses pro agation of wild yeast.

ofwild yeast, can be emplo ed the propagation of lactic acid and 0t er- Application filed October 29, 1925. Serial No. 65,679.

gate between approximately from 20 to 30 C. in an alkaline solution. Other acid forming bacteria which are initially present in crude molasses and which will also propagate-under such conditions are butyric acid bacteria .mentioned above, and bacterium megateroides mentioned in Delbriick, Brennerei Lexicon, Berlin, Germany, 1915, page 519. The propagation of these bacteria in this manner effects a decomposition of theundesired colloids. Subsequently after complete propagation they may be readily killed bythe application ofheat and the solution used to propagate lactic acid'bacteria growing at a relatively high temperature. However, this latter part of the process is only necessary in case very impure molasses is used.

In practice the process is carried out as follows: The crude molasses, or other material containing a relatively high percentage of sucrose, is diluted with water to about twenty five de rees balling. The solution is then made a kaline preferably by the addition of from one fourth to one percent by weight of calcium hydrate to prevent the After thoroug 1y dissolving and mixing "the calcium hydrate, the solution is allowed to stand at a temperature ranging from 20 to. 30 C. for

6 to 24 hours or longer. The cleaning proc- 0.1% by weight is usually sufficient. During this time bacteria prevlously mentioned as being'initially in the crude molasses is allowed to propagate to form certain complex organic acids. Propagation of the bactenitric-aci which is present in many kinds rium. me ateroides serves to decomposeof crude molasses and which is,detrimental to yeast propagation. Propagation of bacteria under. such conditions results in the decomposition of the undesired colloids to form aidark insoluble precipitate and certain soluble compounds which are valuable yeast nutnmnts. settles out of the solutio In case highly infected ployedlfor manufacturin pleting the above, step, t e slowly heated u to. temperature of a out 60 molasses is em:- yeast, after comsolution may be the relatively higher 0. and lactic acid bacteria which propagatefat temperatures The" precipitate readily lactic acid bacteria which to add about 0.1%

from to 60 C. are added. Lactic acid bacteria which will propagate at this temperature have been well known and are described in a publication entitled Mitteilun en fiir Brennerei und Preszhefefw brikation, printed Oct. 18, 1905, by Hemann Brandt, Custrin, Germany, of which I am the author. The bacteria mentioned in thls article, page 2, grow at about 59 (3., the well-known bacterium delbriicke growing at about 50 to C. may also be used. In heating the solution up to this temperature, the germs and bacteria in addition to the have previously been allowed to propagate between 20 to 30 C. are readily killed by a comparatively low temperature and thus the solution is en ficiently sterilized. Sterilization carried on under these conditions will kill detrimental bacteria and germs which otherwise could not be killed either by mineral acids or high temperatures. The organic acids which have been produced by the bacteria propagating:

between 20 to 30 C. are useful in that they form a food for the yeast which is subsequently propagated.

Following the introduction of the lactic acid bacteria, the solution is allowed to stand from 12 to 48 hours at a temperature ranging approximately from 50 to C. Durin this time the decomposition of the colloi s is completed and the may be separated out to leave a c ear liquid. It is preferable to separate out the precipitate several times during the process. Also during the entire process the solution should be kept alkaline until com letion of the propagatlon of the lactic aci bacteria if necessary by adding additional calcium ydrater The solution is now in condition to be employed for the, props ation of yeast. The detrimental germs and bacteria propagating between 20 to 30 C, have been killed by heating to 60 C. However, to insure complete sterilization, the solution may be heated to from 7 0 to 80 C. The lactic acid bacteria which were added are not injurious to the growth of theyeast and need not be killed. It should be understood that other materials may be employed during the above process to roduce an alkaline solution. For example, if ma use any other soluble substances of alka ine reaction such as barium hydrate, sodium hydrate, potassium hydrate, ammonia, alkaline carbonates, silicates or basic phosphates. It is suflicient if the quan- Brevents the propagation of wild tity present yeast but a owe the development of acid orming bacteria.

During or after development of the lactic acid bacteria in the molasses it is profitable by weight of a reducing su once, preferabl sodium thiosulphate, the useof which is ascribed in my copendslimy substances.

1precipitate ing application No. 711,833, previously mentioned. This should be added subsequent to the addition of any oxidizing substance.

When certain kinds of molasses are employed, it is ossible to sufiicicntly disintegrate the col oids and to eliminate certain detrimental bacteria by merely promoting the propagation of bacteria at the higher temperatures of from approximately 50 to 60 C. in a dilute alkaline solution of the molasses, thus eliminating the step of promoting the growth of bacteria propagating at from 20 to 30 C.

The solution resulting from this process is lacking in certain yeast foods and accordingly it is necessary to add phosphates and ammonia salts or organic solutions made from grain. The resulting solution is then, diluted with water and with yeast in any well known manner and the process of yeast propagation completed.

Yeast which is manufactured from a solution prepared by this process will be of highest quality and texture and will be free from It may }be readily compressed with or without the addition of starch and will not readily spoil.

claim:

1. The process of preparing crude molasses for the manufacture of yeast comprismg decomposing colloids in said molasses to form afprecipitate by promoting the propagation o lactic acid bacteria in an alkaline solution of said molasses.

2. The process of preparing crude molasses for the manufacture of yeast comprismg promoting the propagation of lactic acid bacteria in a dilute solution of the molasses maintained at a temperature of from 20 to 30 0., the solution being maintained alkaline to prevent the propagation of wild yeast.

pitched or seeded 3. The Process of preparing molasses for the manu acture of yeast comprising adding l ving lactic acid bacteria'to a. dilute solutron of the molasses, the bacteria bein such aswill propagate at a temperature su stantially from 50 to 60 C., and maintaining the solution at a temperature of from 50 to 60 C. for a substantial eriod, to complete the decomposition of t e 'colloids and to form solub e yeast nutriments and a preci itate readily separable from the solution,t 6 solution being maintained alkaline through. out the process. I 4. The process of preparing crude molasses for the manufacture of yeast, the molasses initially containing lactic acid bacteria which will props ate at a temperature of from 20 to 30 (1., t e process com risi lpromoting the pro'pa t1on of 19.01310 adid acteria in a dilute so ution of themolasses maintained at said temperature for a substantlal period, killing said bacteria b the application of .a higher temperature,

, living lactic acid bacteria of a variety which lasses for the manufacture-of yeast compriswill propagate at a temperature of from to (l and promot ng the propagatlon of\ said latter bacteria in said solutlon at said last named temperature, the solution being maintained alkaline throughout the process.

5. The process of preparing crude rn0- lasses for the manufacture of yeast comprising promoting the propagation of lactic acid forming bacteria in a dilute alkaline solution of the molasses to which is added an oxydizing substance.

6. The'process of preparing molasses for the manufacture of yeast comprising romotingthe propagation of lactic acid acteria in a dilute alkaline solution of the molasses and adding a reducing substance to said solution.

7. The process'of preparing molasses for the manufacture of yeast comprising promoting the propagation of lactic acid bacteria. in a dilute alkaline solution of the molasses and. adding sodium thiosulphateto said solution;

8.-The process of preparing crude moing romoting the propagation of lactic acid orming bacteria in a dilute alkaline solution of the molasses and adding an oxydizing substance and a reducing substance subsequent to the addition of the oxydizing substance.

9. The process of preparing crude molasses for the manufacture of yeast, the molasses initially containing lactic acid forming bacteria which will propagate at atemperature of from 20 to 30 (1,, the process comprising promoting the propagation of said bacteria in a dilute alkaline solution of said molasses.

10. The process of preparing crude mo-' ing promoting the propagation of said base teria in a dilute solutionofsaid molasses at a temperature from 20 to 3Q (1, the solution being maintained alkaline to prevent the propagation of wild yeast.

In testimony whereof, I have hereunto set In hand.

y REINHOLDKUSSEROW, 

